Nowadays, display devices tend to being with large-size and high-resolution along with ever-increasing user demands. In order to satisfy the aforesaid trend, the number of sub-pixel units in a display device is increasing, but because of the large number of sub-pixel units, non-uniformity of display luminance often occurs when the display device displays an image. In order to improve uniformity of display luminance of the display device, it is necessary to acquire, with a sub-pixel unit as a basis, data information representing luminance capability of respective sub-pixel units, which corresponds to the sub-pixel units one to one, adopt an external compensating method based on the data information to compensate for luminance of the sub-pixel units, thereby improving uniformity of display luminance of the display device.
However, the amount of the data information is also very large due to the excessive number of sub-pixel units, and a significant amount of memory is required to store the data information. In order to reduce the memory occupied by the storage of the data information, it needs to compress the data information. Since variation ranges of the data information representing the luminance capability of the sub-pixel units have a certain correlation, meanwhile, and the data information representing the luminance capability of the sub-pixel units also has certain independence because the respective sub-pixel units are independent, if a lossless compression is adopted for the data information, it can not effectively reduce the memory occupied by the storage of the data information; if a lossy compensation is adopted for the data information, it will compromise accuracy of the data information, resulting in that it is impossible to make accurate compensation for the display device based on the decompressed data information, so luminance uniformity of the display device cannot be accurately improved.